• Geotechnical Engineering
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• v.21 no.10
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• pp.52-55
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• 2005

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.44 no.7
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• pp.72-76
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• 2015

• Journal of the korean Society of Automotive Engineers
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• v.16 no.1
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• pp.22-30
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• 1994

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.35 no.11
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• pp.10-14
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• 2006

• Air Cleaning Technology
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• v.31 no.4
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• pp.12-22
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• 2018

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.1969-1975
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• 2012

The air brake system used in heavy vehicle is very important from the point of safety due to its weight. In general, air brake system generates relatively long response time and large loss of pressure. It is known that the response time can be decreased by optimal design of brake system, i.e., by increasing the system pressure, minimizing the air line, and material of components. In this study, We developed experimental rigs for the measurement of braking response of heavy duty trucks and compared with the simulated results obtained from the net work fluid flow system analysis code (FLOWMASTER). The effect of several parameters such as, system pressure, diameter of pipe, chamber temperature on the brake response performance have been examined.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.581-588
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• 2013

We developed the three channel lidar system to measure stratospheric aerosols at the Gwangju Institute for Science and Technology (GIST), a suburban site in Republic of Korea. The system provides backscatter coefficient (${\beta}$) at 532 and 1064 nm as well as depolarization ratios (${\delta}$) at 532 nm ($2{\beta}+1{\delta}$) using the doubled Nd:YAG laser wavelength at 532 and 1064 nm. The lidar system is optimized to measure stratospheric aerosols such as volcanic ashes. This paper describes the details of the optical setup, data acquisition system, and analysis method. This study shows an example of measuring stratospheric aerosols emitted by the volcanic eruption which occurred in Mt. Nabro ($13.37^{\circ}$ N, $41.70^{\circ}$ E).

• Land and Housing Review
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• v.12 no.2
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• pp.91-97
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• 2021

High levels of fine dust is an increasing health concern in major cities such as Seoul. To improve the indoor air quality of apartments, this study examined the ability of an air shower system installed in an apartment unit to remove fine dust (as defined by ISO 12103-A2) from various clothing items of building occupants entering their apartment. Results of the experiment indicate that an air shower system is effective in removing final dust from clothing after one pass through the system. The fine dust removal efficiency for various clothing items was 74% for a dress suit, 70.6% for hiking clothes, 63.3% for knit-wear, 50.5% for a cotton t-shirt, and 38.8% for a coat. Fine dust removal efficiency increased with a second and third pass through the air shower system by an average of 9.1 and 13.9 percentage points respectively compared to a single pass through the system.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.63-71
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• 2023

In the present study, the effect of pitch amplitude on the unsteady aerodynamics of a NACA 0012 airfoil is numerically investigated. When the frequency ratio is equal to 1.0, airfoil pitching with 20 and 30 degrees of pitch amplitude shows almost small lift generation, but the lift is significantly increased in case of 10-degree pitch amplitude. When the frequency is 0.5, the lift coefficients have large values, and the lift increases with a decrease in pitch amplitude. When the frequency ratio is 1.0, the airfoil generates large thrust. The thrust decreases as the pitch amplitude decreases. When the frequency ratio is 0.5, drag is generated for the 30-degree pitch amplitude, but the thrust is generated for 10-degree pitch amplitude. In future, the effect of heave amplitude on the unsteady aerodynamics of the airfoil will be studied.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.5
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• pp.33-42
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• 2010

In this study, we have proposed a simple cardiorespiratory monitoring method based on displacements of human body which occurs due to periodic heartbeat and breathing. The proposed system consists of an aircushion, pressure sensing hardware and heartbeat and respiration signals extraction algorithm. The aircushion was used for unconstrained measurement of the respiration and heartbeats without a sensor attached on the subject's skin surface. The displacements of subject sitting on the aircushion cause small pressure variations. These variations are amplified and filtered with the pressure sensing hardware. Finally, heart rate and respiration rate are extracted by signal processing algorithm based on frequency domain filter. To evaluate the performance, extracted respiration and heart rate from proposed system were compared with conventional methods. The average sensitivity of respiration and heart rate are 98.67% and 99.24%, respectively. These results show the proposed method has advantages of installing and processing simplicity so as to be used easily in unconstrained respiration and heart rate monitoring in daily life.